CN103574231B - A kind of method of construction of thermal insulation of thermal insulation pipeline joint - Google Patents

Abstract

The invention provides a novel heat-insulating construction method for heat-insulating pipe joints. In the step of forming the outer protective layer, a sealing rubber strip is first installed in the installation area adjacent to the outer wall of the outer protective pipe, and then a thermal insulation strip is sheathed on the outer wall of the heat-insulating layer. The shrinkable sleeve is used as the outer protective layer, and the two ends of the heat-shrinkable sleeve are respectively lapped on the installation area of the adjacent outer protective tube and just cover the installation area. After lapping, the distance between the sealing strip and the end of the heat-shrinkable sleeve is certain distance, and finally heat the heat-shrinkable sleeve so that during the shrinkage process of the heat-shrinkable sleeve, the sealing strip melts and seals the end of the heat-shrinkable sleeve and the outer protective tube. By setting the sealing rubber strip in the installation area, and the sealing rubber strip is at a certain distance from the end of the heat-shrinkable sleeve, it can be ensured that when the heat-shrinkable sleeve shrinks, the molten sealing rubber strip can melt and overflow to the edge of the installation area, thereby The end of the heat-shrinkable sleeve is sealingly connected to the end of the adjacent outer protective tube.

Description

A construction method for heat insulation of heat insulation pipe joints

technical field

The invention relates to a novel heat-insulating construction method for heat-insulating pipe joints, and belongs to the technical field of heat-insulating heat-insulating pipe joints for medium transport.

Background technique

In the fields of central heating, cooling, oil and gas, etc., the pipelines used for medium transportation need to be insulated to ensure the insulation performance of the pipelines during the medium transportation process. Insulated pipes are generally prefabricated in the factory according to the length, and then installed on site to form joints at the joints of two insulated pipes. In the entire insulated pipe network, the quality of the joint installation will have a greater impact on the service life of the entire pipe network. Impact.

In the prior art, the construction methods for thermal insulation treatment of thermal insulation pipeline joints mainly include the following two types:

1. Use heat-shrinkable tape sleeves to insulate the pipe joints. During specific construction, first, weld and fix the joints of two adjacent sections of heat-insulated pipes; then, connect HDPE sleeves to the joints as an outer sheath. Among them, the two ends of the HDPE sleeve tube are respectively lapped on the outer protection pipes of two adjacent sections of heat-insulated pipes to form a lap seam, and the lap seam is wrapped with a heat shrinkable tape, and the cross-linked polyethylene material on the heat shrinkable tape shrinks when heated. In this way, the lap seam is sealed; finally, a hole is opened on the HDPE sleeve tube, and a polyurethane thermal insulation layer is formed between the HDPE sleeve tube and the interface by foaming. This construction method makes use of the good sealing effect of the heat shrinkable tape, but during the operation of the pipe network, the pipe network will expand and contract due to the temperature, which will cause the HDPE sleeve to move, and the periodic movement will make the HDPE sleeve It cannot be tightly combined with the polyurethane insulation layer, and will eventually be completely separated from the polyurethane insulation layer. The HDPE sleeve tube and soil that are separated from the polyurethane insulation layer will aggravate the damage to the heat shrinkable tape, affect the sealing of the joint, and then affect the joint. The thermal insulation performance, and this construction method is limited to the thermal insulation construction of small diameter pipe joints.

2. Use the electrothermal fusion welding sleeve to insulate the pipe joints. During the specific construction, firstly, weld and fix the joints of two adjacent sections of heat-insulated pipes, and then connect the HDPE reel embedded with electric heating wires around the inner wall to the polyurethane The heat insulation layer is used as the outer protective layer at the interface, in which, the two ends of the HDPE sleeve pipe are respectively lapped on the outer protective pipes of two adjacent sections of heat insulation pipes to form a lap seam, and then the electric heating wire is energized by an electric fusion welding machine. The contact interface of the two HDPEs is heated and melted so that the two ends of the HDPE sleeves are sealed and connected to the outer protective tubes of the adjacent two sections of heat-insulated pipes; finally, the foaming liquid is poured into the HDPE sleeves. Polyurethane insulation is formed between the HDPE sleeve and the joint. The strength of the joint constructed by this method is relatively high, but it has high requirements for equipment, operation level and construction quality. It will cause a gap between the HDPE hot-melt sleeve and the outer protective pipe, which reduces the sealing performance between the two, thereby reducing the thermal insulation performance of the thermal insulation pipe joint.

In addition, in the above-mentioned construction methods of the prior art, the polyurethane insulation layer is mostly formed by on-site foaming, and it is necessary to open foam holes and vent holes on the HDPE sleeve, although after the polyurethane insulation layer is formed, the foam holes will , The vent hole is sealed and restored, but due to the different sealing methods and different stability, this is still an important hidden danger of the airtightness of the joint.

To sum up, the above-mentioned two construction methods of heat insulation pipe joints in the prior art are affected by the construction conditions and the inherent defects of the sealing structure itself. During the construction process, the sealing effect of the heat insulation pipe joints formed during construction is often unable to be guaranteed, thus It affects the overall insulation performance of the insulation pipeline.

Contents of the invention

Therefore, the technical problem to be solved by the present invention is to overcome the problem in the prior art that the thermal insulation construction method of the thermal insulation pipeline joint makes the poor sealing of the thermal insulation pipeline joint caused by the construction, which leads to the decrease of the thermal insulation performance of the thermal insulation pipeline, and at the same time overcomes the need in the prior art. Holes are opened on the sleeve or the sleeve, and there is a problem of hidden sealing performance at the opening, thereby providing a construction method for heat-insulating pipe joints with good sealing performance, no need to open holes on the sleeve in advance, and excellent thermal insulation performance.

To this end, the present invention provides a construction method for thermal insulation of heat-insulated pipeline joints, including the step of joining the exposed ports of the working pipes of two adjacent sections of heat-insulated pipelines to form an interface area; using a mold to foam on site in the interface area The step of forming the heat insulation layer; and the step of forming the outer sheath on the outer wall of the heat insulation layer and the outer wall of the outer sheath of the adjacent two sections of the heat insulation pipeline; in the step of forming the outer sheath, first A sealing strip is installed in the installation area adjacent to the outer wall of the outer protective tube, and then a heat-shrinkable sleeve is set on the outer wall of the heat-insulating layer as an outer protective layer, and the two ends of the heat-shrinkable sleeve are respectively lapped on the corresponding Adjacent to the installation area of the outer protective tube and just covering the installation area, the sealant strip is a certain distance away from the end of the heat-shrinkable sleeve after lapping, and finally the heat-shrinkable sleeve is heated so that the During the shrinking process of the heat-shrinkable sleeve, the sealing strip melts and seals the end of the heat-shrinkable sleeve and the outer protective tube.

In the step of forming the outer sheath, the heat-shrinkable sleeve is a cross-linked polyethylene sleeve.

In the step of forming the outer sheath, before installing the sealing strip, a step of preheating the installation area is also included.

In the preheating step, the preheating temperature is 50-70°C.

In the step of installing the sealing rubber strip, one end of the sealing rubber strip is wound around the outer circumference of the installation area for at least one week, until the overlapping is fixed on the other end of the sealing rubber strip, and an overlap of at least 30 mm is formed length.

After the two ends of the heat-shrinkable sleeve are respectively lapped on the installation area of the adjacent outer protective tube, the distance between the sealing strip and the end of the heat-shrinkable sleeve is at least 10 mm.

The overlapping lengths of the two ends of the heat-shrinkable sleeve on the installation area of the adjacent outer protective tube are equal.

In the step of heat-treating the heat-shrinkable sleeve, first start heating from the middle of the lengthwise direction of the heat-shrinkable sleeve from bottom to top, and then heat uniformly to both sides one by one in the same way. When the radial shrinkage is completed and the sealing rubber strip in the molten state seals the end of the heat-shrinkable sleeve and the adjacent outer protective tube, the heating is stopped.

In the step of heat-treating the heat-shrinkable sleeve, flame heating is used.

The sealing strip is a hot-melt adhesive strip.

In the step of forming the heat insulating layer, the foaming solution used contains isocyanate component, polyether polyol and auxiliary agent to form a polyurethane foam layer.

In the step of forming the polyurethane foam layer by mold foaming, the mold used includes a coiled plate and a locking device positioned on the outer wall of the coiled plate. Before foaming, the diameter of the pre-foamed polyurethane foam layer is Both ends of the coiled plate are curled into a cylindrical shape, and then a locking device is used to lock the rolled plate into the cylindrical shape.

In the step of forming the polyurethane foam layer by mold foaming, after curling the two ends of the rolling board into a cylindrical shape, two locking blocks arranged at opposite intervals on the rolling board and binding the locking blocks The locking connecting part is used as a locking device to lock the cylindrical shape formed by the rolling plate.

The locking block used is an angle steel fixedly connected to the coiled plate, and the connecting part is a chain steel ring; the two angle steels are perpendicular to one side of the coiled plate, and are formed with more than one corresponding to each other. A notch, the width of the notch is suitable for clamping the chain steel ring in the notch.

The coiled plate used is also provided with a mounting strip, the length of the mounting strip is consistent with the axial length of the coiled plate, the angle steel is set to four, and two correspondingly evenly installed on the mounting strip superior.

The rolling plate is provided with injection holes and exhaust holes.

The coiled plate used is rolled from a thermoplastic resin shell or plate.

After the heat insulation layer is formed by foaming, the outer wall of the heat insulation layer is attached to prevent the gas in the heat insulation layer inside the heat shrinkable sleeve and/or the gas and moisture in the external environment A barrier layer to flow through the heat shrink sleeve.

The barrier layer is a plastic film or aluminum foil attached to the outer wall of the heat insulating layer.

The plastic film is a single-layer film or a mixture of polyethylene terephthalate, polyethylene naphthalate, polyethylene-vinyl acetate copolymer or ethylene-vinyl alcohol copolymer A single-layer film formed later, or a composite film formed by stacking multiple single-layer films.

Compared with the prior art, the technical solution of the present invention has the following advantages:

1. The present invention provides a new construction method for thermal insulation of heat-insulated pipe joints. In the step of forming the outer protective layer, first install a sealing strip in the installation area adjacent to the outer wall of the outer protective pipe, and then install it on the outer wall of the outer protective pipe. Heat-shrinkable sleeves are set on the outer wall of the heat-insulating layer as an outer protective layer, and the two ends of the heat-shrinkable sleeves are respectively overlapped on the installation area of the adjacent outer protection tube and just cover the installation area. Afterwards, the sealing strip is at a certain distance from the end of the heat-shrinkable sleeve, and finally the heat-shrinkable sleeve is heated so that during the shrinking process of the heat-shrinkable sleeve, the sealing strip melts and seals the heat-shrinkable sleeve. Sleeve with the end of the outer protective tube. By arranging the sealing rubber strip in the installation area, and the sealing rubber strip is at a certain distance from the end of the heat-shrinkable sleeve, it can be ensured that when the heat-shrinkable sleeve shrinks, the molten sealing rubber strip can melt and overflow to the The edge of the mounting area thereby sealingly connects the end of the heat-shrinkable sleeve to the end of the adjacent outer protective tube.

2. The construction method of the new heat insulation pipe joint heat insulation provided by the present invention adopts cross-linked polyethylene sleeve as the heat-shrinkable sleeve. The reason is that it is not installed or the installation fails, and a good seal can also be made; even if there is a huge difference in melt flow rate between the XLPE sleeve and the outer protective tube, it can also make the XLPE sleeve and the outer protective tube The outer protection tubes are completely sealed together to ensure the integrity of the joint structure. Moreover, the combination of the flexible bonding function and waterproof function of the sealing strip and the radial shrinkage function of the heat-shrinkable sleeve further increases the sealing between the outer protective tube and the heat-shrinkable sleeve, and improves the performance of the heat-insulating pipe joint. Thermal insulation performance, thereby improving the thermal insulation performance of the entire insulated pipeline. In addition, the construction method of the present invention uses prefabricated polyurethane foam tiles to form the heat insulation layer, which avoids the defects in the prior art that are likely to cause potential safety hazards in the joints when opening foam holes and vent holes on the sleeve tube, and improves the safety of the joints. The tightness further ensures the thermal insulation performance of the joint.

3. The joints formed by the insulation construction method of the heat-insulated pipe joints of the present invention have passed the soil stress test of the standard EN489, which can ensure that the joints are not damaged after 300 times of back and forth, while the heat-insulated joints of the prior art can only be tested under the detection conditions of the standard EN489 , Guaranteed to go back and forth 100 times without damage. It shows that the joint formed by the thermal insulation construction method of the thermal insulation pipe joint of the present invention has excellent mechanical and sealing properties.

4. The construction method for thermal insulation of heat-insulated pipe joints of the present invention, in the step of forming the outer sheath, before installing the sealing strip, the step of preheating the installation area is also included. Preheating the installation area can make the sealant strips softer after being installed in the installation area, and can be easily attached to the installation area, which facilitates the uniform distribution of the sealant strips in the installation area .

5. In the heat-insulating construction method for heat-insulated pipe joints of the present invention, in the preheating step, stop heating when the installation area is heated to 50-70°C. Before installing the sealant strip, stop heating when the installation area is heated to 50-70°C, and heat it to 50-70°C to ensure that the sealant strip is evenly laid on the installation area and adhered to the installation area to avoid When the preheating temperature is too low, the sealant strip will not fit firmly in the installation area, resulting in waterproof and uneven sealing. The defect of the sealing connection between the two ends of the sleeve and the two ends of the outer protective tube.

6. In the construction method for thermal insulation of heat-insulated pipe joints of the present invention, in the step of installing the sealant strip, one end of the sealant strip is wound around the outer circumference of the installation area for at least one week until it is overlapped and fixed on the sealant on the other end of the strip and form an overlap length of at least 30mm. This arrangement enables the sealing rubber strip to be arranged 360 degrees around the outer circumference of the outer protective tube, ensuring better sealing and waterproof performance on the entire outer circumference of the outer protective tube where the sealing rubber strip is arranged.

7. In the heat insulation construction method for heat-insulated pipe joints of the present invention, the overlapping lengths of the two ends of the heat-shrinkable sleeve on the installation area of the adjacent outer protection pipe are equal. This setting can ensure that when the heat-shrinkable sleeve is shrunk, both ends of the heat-shrinkable sleeve have substantially the same amount of shrinkage, thereby ensuring good sealing at both ends and an aesthetic appearance.

8. In the heat-insulating construction method for heat-insulating pipe joints of the present invention, in the step of heat-treating the heat-shrinkable sleeve, first start heating from the middle of the length direction of the heat-shrinkable sleeve from bottom to top, and then follow the same method one by one. Heat evenly on both sides. When the heat-shrinkable sleeve completes radial shrinkage and the sealant strip overflows from the melt to the edge of the installation area, observe the heat-shrinkable sleeve and the outer protective tube. When the rubber strip completely seals the end of the heat-shrinkable sleeve and the ends of the outer protective tubes of the adjacent two sections of heat-insulated pipelines, stop heating. Heating from the middle of the heat-shrinkable sleeve can avoid uneven heat transfer at both ends of the heat-shrinkable sleeve in the length direction during the heating process, and ensure that the heat-shrinkable sleeve shrinks evenly in the length direction, and start heating from the bottom, so that The heat is transmitted from bottom to top, which has a good heat transfer effect, can reduce heating time and improve heating efficiency; after heating in the middle, gradually heat toward both ends of the heat shrinkable sleeve according to the heating sequence from the bottom to the top, which can Reduce the temperature difference between the first heating part and the rear heating part to avoid the defect of uneven shrinkage performance caused by large temperature difference.

9. In the heat-insulating construction method for heat-insulating pipe joints of the present invention, in the step of heat-treating the heat-shrinkable sleeve, a flame heating method is adopted, which is simple and convenient to operate and saves costs.

10. The thermal insulation construction method of the thermal insulation pipe joint of the present invention, in the step of forming the thermal insulation layer, the foaming liquid used contains isocyanate component, polyether polyol and additives. The foaming solution of this kind of composition makes the polyurethane foam formed have low thermal conductivity, high compressive strength, high foam closed cell ratio, and small average pore diameter of foam, which ensures the heat insulation effect of the heat insulation layer.

11. In the heat insulation construction method for heat-insulated pipe joints of the present invention, in the step of foaming a mold to form a polyurethane foam layer, the mold used includes a coiled plate and a locking device located on the outer wall of the coiled plate. Before foaming, Firstly, according to the diameter of the pre-foamed polyurethane foam layer, the two ends of the rolled plate are curled into a cylindrical shape, and then the rolled plate is locked by a locking device. The coiled plate can be rolled into various cylindrical shapes with different inner diameters according to the different outer diameters of the insulation pipe within the allowable range of the length of the rolled plate, that is, the inner diameter of the cylindrical shape rolled by the mold can be adjusted, which can realize that one mold is suitable for multiple Insulation tubes with a variety of outer diameters (within a certain size), which not only saves production costs, but also can roll up the mold when the mold is not in use or when it is transported, so that it occupies a small space and is easy to carry and carry .

12. In the heat insulation construction method for heat-insulated pipe joints of the present invention, a material injection hole is provided on the roll plate, so as to facilitate the injection of foaming liquid into the space formed by the roll and the installation area through the material injection hole, The air vent is provided to facilitate the discharge of the gas generated during the foaming process, thereby avoiding the occurrence of air holes in the product formed by foaming and affecting the quality of the product.

13. The heat insulation construction method for heat-insulated pipe joints of the present invention, after forming the heat-insulation layer, sticking arrangements are made on the outer wall of the heat-insulation layer to prevent the The gas and/or the gas in the external environment and moisture can pass through the barrier layer for the circulation of the heat-shrinkable sleeve. During the use of heat-insulated pipe joints, when the gas or moisture in the external environment penetrates into the barrier layer through the tube wall of the heat-shrinkable sleeve, it is blocked by the barrier layer, so that the gas or moisture in the external environment cannot continue to flow. The layer blocks the flow of gas and moisture in the external environment of the heat-shrinkable sleeve through its tube wall, reducing the influence of the external environment on the structure such as the heat-insulating layer in the sleeve tube or the transport medium in the working tube; When the gas flows under the influence of temperature, the barrier layer also plays a role in blocking the gas from penetrating the pipe wall, thus ensuring the performance of the heat insulating layer. In addition, since the barrier layer is arranged between the heat-shrinkable sleeve and the heat-insulating layer, the barrier layer is not in contact with the external environment, which avoids damage to the barrier layer caused by external objects, and at the same time prevents the barrier layer from directly contacting the water in the external environment. The reduction of the barrier performance caused by contact ensures the life of the barrier layer, that is, the life of the sleeve tube, that is, the life of the heat-insulating pipe joint.

14. The construction method for heat insulation of heat-insulated pipe joints of the present invention, the plastic film is polyethylene terephthalate, polyethylene naphthalate, polyethylene-vinyl acetate copolymer or ethylene-vinyl alcohol copolymer A single-layer film formed by one of them or a single-layer film formed by mixing multiple types, or a composite film formed by stacking multiple single-layer films. Since the above-mentioned materials are all high-barrier materials, high-barrier materials have strong gas and moisture barrier properties, and prevent the problem of reducing the thermal insulation effect of the thermal insulation layer due to moisture and other penetration, which is of great importance for thermal insulation pipelines with a large number of joints meaning.

Description of drawings

In order to make the content of the present invention more easily understood, the present invention will be described in further detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein

Fig. 1 is a schematic diagram of a heat-insulating pipe joint formed by adopting the heat-insulating construction method of the heat-insulating pipe joint in Embodiment 1 of the present invention;

Fig. 2 is the structural representation of a kind of implementation method of the mold in the embodiment 2 of the present invention;

Fig. 3 is the structural representation of another embodiment of the mold in the embodiment 2 of the present invention;

The reference signs in the figure are expressed as: 1, 2-insulated pipe; 3, 4-working pipe; 5-insulated layer; 6-heat-shrinkable sleeve; 7,8-outer protective tube; 9,10-sealing strip; 11-coil; 12-angle steel; 13-chain steel ring; 14-notch; 15-installation strip; 16-injection hole; 17-vent.

Detailed ways

In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific implementation manners of the present invention will now be described with reference to the accompanying drawings.

In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific implementation manners of the present invention will now be described with reference to the accompanying drawings.

Example 1

This embodiment provides a new construction method for insulation of heat-insulated pipe joints, including

A. The step of joining the exposed ports of the working pipes 3, 4 of the adjacent two sections of heat-insulated pipelines 1, 2 to form an interface area;

B. The step of forming the thermal insulation layer 5 by foaming on-site with a mold in the interface area;

C. The step of forming an outer sheath on the outer wall of the heat insulation layer 5 and part of the outer walls of the outer sheath pipes 7, 8 of the adjacent two sections of heat insulation pipelines 1, 2, in the step of forming the outer sheath, first Install sealing strips 9, 10 in the installation area adjacent to the outer walls of the outer protective tubes 7, 8, and then set a heat-shrinkable sleeve 6 on the outer wall of the heat-insulating layer 5 as an outer sheath, and the heat-shrinkable The two ends of the sleeve 6 are respectively overlapped on the installation area of the adjacent outer protection tubes 7, 8 and just cover the installation area, and the sealing strips 9, 10 are separated from the heat-shrinkable sleeve after overlapping. 6 ends at a certain distance, and finally heat the heat-shrinkable sleeve 6, so that during the shrinking process of the heat-shrinkable sleeve 6, the sealing strips 9 and 10 melt and seal the heat-shrinkable sleeve 6 and the outer sleeve. The ends of the protective tubes 7, 8, wherein a cross-linked polyethylene sleeve is used as the heat-shrinkable sleeve 6.

In this embodiment, the exposed lengths of the working tubes 3 and 4 are 150 mm respectively, the length of the heat-shrinkable sleeve 6 is 660 mm, and the distance between the sealing strips 9 and 10 is 6 ends of the heat-shrinkable sleeve The width of the sealing strips 9 and 10 is 70 mm.

As a modification of this embodiment, the exposed lengths of the working tubes 3 and 4 can be adjusted within the range of 150-250 mm according to construction needs, and the length of the heat-shrinkable sleeve 6 can be 660-680 mm. Adjust according to the construction needs within the range.

In the construction method of this embodiment, by setting the sealing strips 9 and 10 in the installation area, and the sealing strips 9 and 10 are at a certain distance from the end of the heat-shrinkable sleeve 6, it can be ensured that the heat-shrinkable sleeve 6 When shrinking, the molten sealing strips 9 and 10 can melt and overflow to the edge of the installation area, thereby sealingly connecting the end of the heat-shrinkable sleeve 6 and the adjacent outer protective tubes 7 and 8 . The sleeve tube made of cross-linked polyethylene material is used as the heat-shrinkable sleeve 6, because cross-linked polyethylene has extremely excellent shrinkage performance and adhesion performance, even if the sealing strips 9 and 10 are not installed or installed due to construction quality reasons failure, a good seal can be made; even with a large difference in melt flow rate between the XLPE sleeve and the outer protective tube, the XLPE sleeve and the outer protective tube can be sealed7, 8 Completely sealed together to ensure the integrity of the joint structure. Moreover, combining the waterproof function of the flexible bonding of the sealing strips 9, 10 and the heating radial contraction function of the heat-shrinkable sleeve 6 further increases the sealing performance between the outer protective tubes 7, 8 and the heat-shrinkable sleeve 6, The thermal insulation performance of the thermally insulated pipe joint is improved, thereby improving the thermal insulation performance of the entire thermally insulated pipe.

In this embodiment, in the step of forming the outer sheath, before installing the sealing strips 9, 10, a step of preheating the installation area is also included, and in the preheating step, the Stop heating when the above-mentioned installation area is heated to 50-70°C. Before installing the sealing strips 9 and 10, stop heating when the installation area is heated to 50-70°C, and heat to 50-70°C to ensure that the sealing strips 9 and 10 are evenly laid on the installation area and adhered In the installation area, when the preheating temperature is too low, the sealant strips 9 and 10 are not firmly attached to the installation area, resulting in waterproof and uneven sealing. The defect that the two ends of the heat-shrinkable sleeve 6 and the two ends of the outer protective tube 7 and 8 are sealed and connected due to the melting of the strips 9 and 10 in advance.

In this embodiment, in the step of installing the sealing rubber strips 9, 10, one end of the sealing rubber strips 9, 10 is wound around the outer circumference of the installation area for at least one circle until it is overlapped and fixed on the sealing rubber strips. 9, 10 on the other end, and form a lap length of at least 30mm. Of course, as a modification of this embodiment, one end of the sealing strips 9 and 10 can also be wound around the outer circumference of the installation area for two, three or more circles, and after multiple windings, one end can also be Set to overlap on the other end and form a minimum overlap length of 30mm. This kind of arrangement makes the sealing rubber strips 9,10 can be arranged around the outer circumference of the outer protective tubes 7,8 at 360 degrees, ensuring that the outer protective tubes 7,8 are provided with sealing rubber strips 9,10 on the entire outer circumference. Better sealing and waterproof performance. As a modification of this embodiment, multiple sealing strips 9 and 10 may also be arranged side by side. The sealing strips 9 and 10 are horseshoe butter hot-melt adhesives, and of course other existing hot-melt adhesive strips, such as hybrid adhesive strips, can also be used.

In this embodiment, in the step of heat-treating the heat-shrinkable sleeve 6, first start heating from the middle of the lengthwise direction of the heat-shrinkable sleeve 6 from bottom to top, and then heat evenly to both sides one by one according to the same method, When the heat-shrinkable sleeve 6 completes the radial contraction and the sealing strips 9 , 10 in the molten state seal the end of the heat-shrinkable sleeve 6 and the adjacent outer protective tubes 7 , 8 , stop heating.

Using the construction method of this embodiment, heating from the middle of the heat-shrinkable sleeve 6 can avoid uneven heat transfer at both ends of the heat-shrinkable sleeve 6 in the length direction during the heating process, and ensure that the heat-shrinkable sleeve 6 is even in the length direction Shrink, and start heating from the bottom, so that the heat is transferred from the bottom to the top, which has a better heat transfer effect, can reduce the heating time and improve the heating efficiency; after the middle heating, according to the heating sequence from the bottom to the top, toward The two ends of the heat-shrinkable sleeve 6 are gradually heated, which can reduce the temperature difference between the first heating part and the second heating part, and avoid the defect of uneven shrinkage performance caused by a large temperature difference.

In this embodiment, flame heating is adopted in the step of heat-treating the heat-shrinkable sleeve 6 .

The heat-insulated pipe joint formed by the above-mentioned construction method of this embodiment, as shown in Figure 1, has passed the soil stress test of the standard EN489, and can ensure that the joint is not damaged after 300 round-trips, while the heat-insulated joint of the prior art can only be tested in the standard EN489 Under the testing conditions, it is guaranteed that there will be no damage after 100 round trips. It shows that the joint formed by the thermal insulation construction method of the thermal insulation pipe joint of the present invention has excellent mechanical and sealing properties.

Example 2

This embodiment provides a construction method for thermal insulation of heat-insulated pipe joints, which is a further improvement on the basis of Embodiment 1. In this embodiment, in the step of foaming to form the polyurethane foam layer, a portable Joint foaming mold, as shown in Figure 2, the foaming mold includes a coiled plate 11 that can be rolled into a cylindrical shape, and is located on the outer wall of the rolled plate 11, and locks the rolled plate 11 into a cylindrical shape. the locking device. Before foaming, the two ends of the rolled board 11 are curled into a cylindrical shape according to the diameter of the pre-foamed polyurethane foam layer, and then the rolled board 11 is locked in the cylindrical shape with a locking device. The coiled plate 11 can be rolled into various cylindrical shapes with different inner diameters according to the different outer diameters of the heat insulating tubes within the allowable range of the length of the rolled plate, that is, the inner diameter of the cylindrical shape rolled by the mold can be adjusted, so that a mold can be used. Various outer diameters of insulated tubes with various outer diameters (within a certain size range), not only saves production costs, but also can roll up the mold when it is not in use or when it is transported, so that it occupies a small space , easy to handle and carry.

In this embodiment, the locking device includes two locking blocks arranged at intervals on the rolling plate 11, and a connecting part that binds and locks the locking blocks on both sides; the locking blocks In order to fix the angle steel 12 connected on the coil plate 11, the connecting part is a chain steel ring 13; the two angle steels 12 are perpendicular to the one side of the coil plate 11, and are formed with more than one notch 14 corresponding to each other. , the width of the notch 14 is suitable for clamping the chain steel ring 13 in the notch 14; as a preferred embodiment, the length of the angle steel 12 is consistent with the axial length of the coiled plate 1, and the angle steel The gaps 14 on the 12 are set to three.

As a convertible implementation of the above-mentioned embodiment, as shown in Figure 3, the present embodiment is provided with a mounting strip 15 on the coiled plate 11, and the length of the mounting strip 15 is the same as the axial length of the coiled plate 11. Consistently, the number of angle steels 12 is set to four, and two by two are evenly installed on the installation bars 15, and the notch 14 on the angle steel 12 is set to one.

In this embodiment, the coiled plate 11 is provided with a material injection hole 16 and an exhaust gas 17; the material injection hole is used to inject the foam material, and the exhaust hole 17 is used to release the injected foam material during the process. The gas generated during the reaction, so as to avoid the situation that there are pores in the product formed by foaming and affect the quality of the product.

The thickness of the coiled plate 11 is 3-20 mm; when making the mould, it can be selected according to the needs, and the suitable thickness selection can not only ensure that the mould can withstand a certain foaming pressure, but also has flexibility and light weight , reducing the workload of the staff.

On the basis of the above embodiments, in this embodiment, as a preferred embodiment, the coiled plate 11 is rolled from a thermoplastic resin plate, so that the mold has a certain degree of flexibility and can adapt to irregularities in the shape of the pipeline. , such as ellipse, eccentricity, etc., and in each case, it has good sealing performance, and there will be no leakage of material; and the mold is easy to make and can be made on the construction site; if it is in the construction process If the mold is damaged, the staff can obtain local materials and make it, so as to avoid the failure of construction due to the damage of the mold, delaying the construction period and affecting the work progress.

Certainly, as an alternative implementation of the above-mentioned embodiment, the coiled plate 11 may also be coiled from a thermoplastic resin shell or made of metal sheet.

Example 3

This embodiment provides a construction method for thermal insulation of heat-insulated pipe joints, which is a deformation on the basis of Embodiment 1. In this embodiment, after the formation of the thermal insulation layer 5 during the construction process, A plastic film is attached to the outer wall of 5 as a barrier layer, and the barrier layer is located between the outer wall of the heat-insulating layer 5 and the inner wall of the heat-shrinkable sleeve 6 to prevent the heat-shrinkable sleeve 6 from The inner gas in the thermal insulation layer 5 and/or the gas and moisture in the external environment are a barrier layer for the circulation of the heat-shrinkable sleeve 6 .

During the use of the heat-insulating pipe joint, when the gas or moisture in the external environment penetrates into the barrier layer through the tube wall of the heat-shrinkable sleeve 6, it is blocked by the barrier layer, so that the gas or moisture in the external environment cannot continue to flow. The barrier layer blocks the flow of gas and moisture in the external environment of the heat-shrinkable sleeve 6 through its tube wall, reducing the impact of the external environment on the structures such as the heat-insulating layer 5 or the transport medium in the working tube; When the gas flows under the influence of temperature, the barrier layer also plays a role in blocking the gas from penetrating the pipe wall, thereby ensuring the performance of the heat insulating layer 5 . In addition, since the barrier layer is arranged between the heat-shrinkable sleeve 6 and the heat-insulating layer 5, the barrier layer is not in contact with the external environment, avoiding damage to the barrier layer caused by external objects, and at the same time preventing the barrier layer from directly contacting the external environment. The reduction of the barrier performance caused by contact with the water, thereby ensuring the life of the barrier layer, that is, ensuring the life of the sleeve tube, that is, ensuring the life of the heat-insulated pipe joint.

In this embodiment, the plastic film is ethylene-vinyl alcohol copolymer (EVOH) forming a single-layer film. As a modification of this embodiment, the plastic film can also be polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethylene-vinyl acetate copolymer (EVA) A single-layer film formed by one of the above-mentioned materials or a single-layer film formed by mixing a plurality of the above materials, or a composite film formed by stacking each of the above-mentioned materials into a single-layer film. The above materials are all high barrier materials, which have excellent moisture and gas barrier properties, prevent the increase of the thermal conductivity of the thermal insulation layer caused by the penetration of moisture and gas, and ensure that the thermal insulation layer has a good thermal insulation effect.

As a modification of this embodiment, the barrier layer may also be aluminum foil.

Apparently, the above-mentioned embodiments are only examples for clear description, and are not intended to limit the implementation. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. And the obvious changes or changes derived therefrom are still within the scope of protection of the present invention.

Claims (20)

1. a method of construction for thermal insulation of thermal insulation pipeline joint, comprises

The exposed port of the working pipe (3,4) of adjacent two sections of insulated pipings (1,2) is engaged with the step forming interface area;

Mould foam-in-place is adopted to form the step of heat insulation layer (5) in described interface area; And

The outer wall of the outer wall of described heat insulation layer (5) and the outer pillar (7,8) of adjacent two sections of insulated pipings (1,2) is formed the step of outer protective layer;

It is characterized in that: in the step of described formation outer protective layer, first at adjacent described outer pillar (7, 8) in the mounting zone of outer wall, sealing joint strip (9 is installed, 10), then on the outer wall of described heat insulation layer (5) sheathed thermal shrinkage oversleeve (6) as outer protective layer, the two ends of described thermal shrinkage oversleeve (6) are overlapped on adjacent outer pillar (7 respectively, 8) described mounting zone also just in time covers described mounting zone, described sealing joint strip (9 after overlap joint, 10) apart from described thermal shrinkage oversleeve (6) end certain distance, finally heat described thermal shrinkage oversleeve (6), to make in described thermal shrinkage oversleeve (6) contraction process, with described sealing joint strip (9, 10) thermal shrinkage oversleeve (6) and described outer pillar (7 are stated in melting sealed residence, 8) end.

2. the method for construction of thermal insulation of thermal insulation pipeline joint according to claim 1, is characterized in that: in the step of described formation outer protective layer, and thermal shrinkage oversleeve (6) is crosslinked polyethylene oversleeve.

3. the method for construction of thermal insulation of thermal insulation pipeline joint according to claim 1 and 2, is characterized in that: in the step of described formation outer protective layer, before installation sealing joint strip (9,10), also comprises the step of described mounting zone being carried out to preheating.

4. the method for construction of thermal insulation of thermal insulation pipeline joint according to claim 3, is characterized in that: in described preheating step, and preheating temperature is 50-70 DEG C.

5. the method for construction of thermal insulation of thermal insulation pipeline joint according to claim 1 and 2, it is characterized in that: at installation sealing joint strip (9,10) in step, described sealing joint strip (9,10) one end is wound around at least one week around the excircle of described mounting zone, until overlap joint is fixed on the other end of described sealing joint strip (9,10), and form the lap length of at least 30mm.

6. the method for construction of thermal insulation of thermal insulation pipeline joint according to claim 1 and 2, it is characterized in that: be overlapped on adjacent outer pillar (7 respectively at the two ends of described thermal shrinkage oversleeve (6), 8) after on described mounting zone, described sealing joint strip (9,10) is apart from the distance of described thermal shrinkage oversleeve (6) end at least 10mm.

7. the method for construction of thermal insulation of thermal insulation pipeline joint according to claim 1 and 2, is characterized in that: the lap length of two ends on the described mounting zone of adjacent outer pillar (7,8) of described thermal shrinkage oversleeve (6) is equal.

8. the method for construction of thermal insulation of thermal insulation pipeline joint according to claim 1 and 2, it is characterized in that: in the step that described thermal shrinkage oversleeve (6) is heated, first heat from the bottom to top from the centre of the length direction of thermal shrinkage oversleeve (6), again by the same way one by one to both sides homogeneous heating, complete radial contraction described thermal shrinkage oversleeve (6) and make the described sealing joint strip (9 of molten state, 10) end of described thermal shrinkage oversleeve (6) and adjacent outer pillar (7 is sealed, 8), time, heating is stopped.

9. the method for construction of thermal insulation of thermal insulation pipeline joint according to claim 1 and 2, is characterized in that: in the step heated described thermal shrinkage oversleeve (6), adopts flame mode of heating.

10. the method for construction of thermal insulation of thermal insulation pipeline joint according to claim 1 and 2, is characterized in that: described sealing joint strip (9,10) is hot melt adhesive tape.

The method of construction of 11. thermal insulation of thermal insulation pipeline joint according to claim 10, is characterized in that: in the step of described formation heat insulation layer (5), containing isocyanate component, polyether polyol and auxiliary agent in the foaming liquid of employing, forms polyurethane foam.

The method of construction of 12. thermal insulation of thermal insulation pipeline joint according to claim 10, it is characterized in that: formed in the step of polyurethane foam adopting mould foaming, the locking device that the described mould adopted comprises roll bending (11) and is positioned on described roll bending (11) outer wall, before foaming, first according to the diameter of the polyurethane foam of prefoam, the two ends of described roll bending (11) are curled into tubular, the described tubular locking then adopting locking device to be rolled into by described roll bending (11).

The method of construction of 13. thermal insulation of thermal insulation pipeline joint according to claim 12, it is characterized in that: formed in the step of polyurethane foam adopting mould foaming, after the two ends of described roll bending (11) are curled into tubular, adopt the described tubular locking that relative spacing is arranged on two locking blocks on described roll bending (11) and described locking block bundle is rolled into by described roll bending (11) as locking device around the connected element of locking.

The method of construction of 14. thermal insulation of thermal insulation pipeline joint according to claim 13, is characterized in that: the described locking block of employing is for being fixedly connected on the angle steel (12) on described roll bending (11), and described connected element is chain steel loop (13); On angle steel described in two (12) one side perpendicular to described roll bending (11), form mutually corresponding more than one breach (14), the width of described breach (14) is applicable to described chain steel loop (13) to be stuck in described breach (14).

The method of construction of 15. thermal insulation of thermal insulation pipeline joint according to claim 14, is characterized in that:

The described roll bending (11) adopted also is provided with mounting bar (15), the length of described mounting bar (15) is consistent with the axial length of described roll bending (11), described angle steel (12) is set to four, and is evenly arranged on described mounting bar (15) accordingly between two.

The method of construction of 16. thermal insulation of thermal insulation pipeline joint according to claim 15, is characterized in that:

It is characterized in that: described roll bending (1) is provided with material hole (16) and exhaust port (17).

The method of construction of 17. thermal insulation of thermal insulation pipeline joint according to any one of claim 12-16, is characterized in that: the described roll bending (1) of employing is formed by thermoplastic resin shell or coiled sheet system.

The method of construction of 18. thermal insulation of thermal insulation pipeline joint according to claim 1 and 2, it is characterized in that: after foaming forms described heat insulation layer (5), on the outer wall of described heat insulation layer (5), laminating arranges and is used for prevention and is arranged in the barrier layer that the inner gas of described heat insulation layer (5) of described thermal shrinkage oversleeve (6) and/or the gas of external environment and moisture circulates through described thermal shrinkage oversleeve (6).

The method of construction of 19. thermal insulation of thermal insulation pipeline joint according to claim 18, is characterized in that: described barrier layer is plastic pellicle or the aluminium foil of the outer wall setting of the described heat insulation layer of laminating (5).

The method of construction of 20. thermal insulation of thermal insulation pipeline joint according to claim 19, it is characterized in that: the single thin film that described plastic pellicle is polyethylene terephthalate, the single thin film of a kind of formation in PEN, polyethylene vinyl acetate copolymer or ethylene-vinyl alcohol copolymer or multiple mixing are formed afterwards, or superposed the laminated film formed by multiple single thin film.